Retentive Properties of TiN-coated Novaloc and Locator Overdenture Abutments
Dana Jafarpour1*, Eric Krochmalnek1*, Lei Wu2, Damiano Pasini2, Raphael Freitas de Souza1
1 Faculty of Dental Medicine and Oral Health Sciences, McGill University; 2 Dept. Mechanical Engineering, McGill University
*Equal contribution
Background: Edentulism is a chronic, irreversible condiƟon that can profoundly impact wellbeing and quality of life. The 2-implant mandibular overdenture is the minimum standard of care for edentulism. However, the 2-implant overdenture’s reliance on a reduced number of attachments requires routine reactivation or replacement of retentive components, which can be inefficient and burdensome. The Novaloc system matrices are made of polyetheretherketone (PEEK), a more resistant material than traditionally used nylon, and contains a titanium nitride (TiN) coating.
Objective: To compare retentive force longevity of Novaloc-TiN and Locator abutments for 2-implant overdentures after undergoing insertion-removal and compressive cyclic loading, representing masticatory forces equivalent to 1 week, 1, 3, 6 and 12 months of wear.
Methods: Compressive cycling and insertion-removal of 2-implant TiN-coated Novaloc and Locator overdenture abutments embedded into 3D-printed acrylic blocks were performed (n=10 each). For compressive cycling, force (66.7 N) was applied at the block’s centre using a Bose ElectroForce Fatigue Testing machine over a sum of 300,000 cycles per specimen. The retentive force was recorded at baseline and after compression cycles of 5k, 25k, 75k, 150k, and 300k, and insertion removals of 23, 270, 540, and 1080 cycles. Deformation and crystallization were assessed using micro-computed tomography and differenƟal scanning calorimetry coupled with thermal gravimetric analysis.
Results: Compressive cycling of the 2-implant overdenture yielded a greater net retentive force for the Locator abutments relative to the TiN-coated Novaloc system at simulated mastication equivalent to 1 week, 1, 3, 6 and 12 months of wear. However, Locator abutments displayed fluctuating retentive force throughout the 300,000-cycle duration. Retention forces for the Novaloc system had no significant differences between the baseline and following 300,000 cycles, indicating consistent retention throughout the cycling duration. Similarly, insertion-removal cycling resulted in retention loss for Locator, whereas Novaloc showed more consistency over time.
Conclusions: The Novaloc system offers superior durability following compressive and inserƟonremoval cycling. This indicates more longevity for retentive forces relative to the Locator overdenture attachments system, despite lower overall retention.